TV broadcasting system discrimination apparatus and method

摘要

The present invention relates to an apparatus for determining a broadcast method of a TV and a method thereof, unlike the conventional method which can simply discriminate only a broadcast method of an M broadcast method (4.5 [MHz]) and an i broadcast method (6.0 [MHz]). According to the present invention, a frequency that the microcomputer can recognize a tuning frequency variable stage generating a tuning frequency signal whose frequency is determined according to a pulse width modulation output (PWM) and a partial frequency signal of the tuning frequency signal generated by the tuning frequency variable stage is generated. A divider means for dividing and outputting the signal, and a signal presence judging means for judging whether a predetermined level of voice signal is output from the voice intermediate frequency processing / demodulator which demodulates the voice intermediate frequency signal according to the tuning frequency signal, and the tuning means. The pulse width modulation output PWM is supplied to the tuning frequency variable step to change the frequency of the tuning frequency signal output from the variable frequency step, and the pulse width While increasing the modulation output PWM and determining that the audio signal having a predetermined level is output from the voice intermediate frequency processing / demodulator, the signal recognition unit recognizes the frequency f of the frequency signal output from the frequency division means. With a microcomputer to determine the current broadcasting method, the broadcasting method is M broadcasting method (4.5 [MHz]), i broadcasting method (6.0 [MHz]), B / G broadcasting method (5.5 [MHz]) or D / It is possible to determine whether it is K broadcasting system (6.5 [MHz]), and also to determine whether each broadcasting system is MONO, A2, or even NICAM accurately.